This project uses functional MRI to examine how several areas of the brain function cooperatively during the comprehension of language. Some of the classical language areas (Broca's area, Wernicke's area, and their right hemisphere homologues) have been found to be activated during language comprehension, but the precise combination of areas and their degree of activation depends on the nature of the task. Instead of using brain imaging to ask only "which brain areas activate?" we will ask "what volume of brain tissue activates in various nodes of a network under different task conditions?" The experiments will manipulate the nature of the comprehension task and the difficulty of the computations (the amount of computation that is required), to learn how the behavior of each brain area is affected. This mapping between the information processing that the comprehension task requires and the volume of brain activation in each language area can indicate how and where the computations are being performed in the brain. Using the topographic and volumetric pattens of the brain activation, we will construct models of the coordination and interaction of the underlying brain subsystems involved in sentence comprehension. The studies will use cutting- edge technologies and methodologies, exploiting the speed and sensitivity of high field echo-planar fMRI to answer questions about the functional connectivity and organization of the brain systems underlying language processing. Even though the comprehension that arises from the normal coordinated action of these areas is taken for granted in normal adults and children, its disruption after stroke and in order neurological diseases makes evident the need to understand its brain basis. The health-related implication of this research is the rather direct potential for providing a method for assessing brain function during language processing pre-surgically and after stroke, and providing results from normal individuals which can be used as normative data.